In a news conference at Holyoke City Hall on Monday afternoon, Police Chief James Neiswanger said that the investigation into the firefighter led them to investigate a Holyoke police officer for drug possession as well.

Neiswanger said that the investigation centers around the use of the drug suboxone, a semi-synthetic drug that is often used in the treatment of people with opiate addictions, but one that has also been abused.

According to Neiswanger, the investigation began on Wednesday, when state police conducted a traffic stop in which suboxone was found. The man who they pulled over told the troopers that he was making a delivery to an on-duty Holyoke firefighter who was dealing with a prescription pill addiction. State police notified Holyoke Police, and they staked-out Holyoke Fire headquarters, where Neiswanger said that the firefighter in question came out to meet his “drug dealer contact.”

The firefighter then gave them information that led them to suspect the Holyoke police officer.

The chief said that the officer was interviewed by police on Thursday prior to the beginning of his next scheduled shift. Neiswanger said that the investigators had serious concerns about the officer, so he was placed on administrative leave, and his service weapon was taken.

The firefighter resigned his position with the department on Friday, and Neiswanger said that the police officer submitted his letter of resignation on Monday morning.

The names of the officer and firefighter have not been released, though the chief did say that the police officer in question was a “young patrolman” who was not on any special assignment. Neiswanger said that there is no word yet on whether there are other public safety employees involved, and that there is a criminal and an internal investigation into the matter going on at this time.

Neither the firefighter nor the police officer have been arrested, and no drugs have been seized.

Mayor Alex Morse said that this type of activity will not be tolerated, and that all members of the police and fire departments will undergo drug testing.